From 91c46de4aa3d3a910033f91803148a614749964a Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Sat, 26 Feb 2022 20:33:42 +0800
Subject: [PATCH 01/13] fix(relup): inject relup instructions to the end of
 relup file

---
 rebar.config.erl             |  3 +-
 scripts/inject-relup.escript | 58 ++++++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100755 scripts/inject-relup.escript

diff --git a/rebar.config.erl b/rebar.config.erl
index ce8933570..11db1abb1 100644
--- a/rebar.config.erl
+++ b/rebar.config.erl
@@ -129,7 +129,8 @@ prod_overrides() ->
     [{add, [ {erl_opts, [deterministic]}]}].
 
 relup_deps(Profile) ->
-    {post_hooks, [{"(linux|darwin|solaris|freebsd|netbsd|openbsd)", compile, "scripts/inject-deps.escript " ++ atom_to_list(Profile)}]}.
+    {post_hooks, [{"(linux|darwin|solaris|freebsd|netbsd|openbsd)", release,
+                        "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx"])}]}.
 
 profiles() ->
     Vsn = get_vsn(),
diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
new file mode 100755
index 000000000..a7ba23689
--- /dev/null
+++ b/scripts/inject-relup.escript
@@ -0,0 +1,58 @@
+#!/usr/bin/env escript
+
+%% This script injects implicit relup instructions for emqx applications.
+
+-mode(compile).
+
+-define(ERROR(FORMAT, ARGS), io:format(standard_error, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
+-define(INFO(FORMAT, ARGS), io:format(user, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
+
+usage() ->
+  "Usage: " ++ escript:script_name() ++ " <path-to-release-dir>".
+
+main([Dir]) ->
+  case filelib:is_dir(Dir) of
+    true ->
+      ok = inject(Dir);
+    false ->
+      ?ERROR("not a valid dir: ~p", [Dir]),
+      erlang:halt(1)
+  end;
+main(_Args) ->
+  ?ERROR("~s", [usage()]),
+  erlang:halt(1).
+
+inject(Dir) ->
+  RelupFiles = filelib:wildcard(filename:join([Dir, "releases", "*", "relup"])),
+  lists:foreach(fun(File) ->
+      case file:consult(File) of
+        {ok, [{CurrRelVsn, UpVsnRUs, DnVsnRUs}]} ->
+          ?INFO("injecting instructions to: ~p", [File]),
+          UpdatedContent = [{CurrRelVsn, inject_relup_instrs(CurrRelVsn, UpVsnRUs),
+                              inject_relup_instrs(CurrRelVsn, DnVsnRUs)}],
+          file:write_file("/tmp/" ++ filename:basename(File), term_to_text(UpdatedContent));
+        {ok, _BadFormat} ->
+          ?ERROR("bad formatted relup file: ~p", [File]);
+        {error, Reason} ->
+          ?ERROR("read relup file ~p failed: ~p", [File, Reason])
+      end
+    end, RelupFiles).
+
+inject_relup_instrs(CurrRelVsn, RUs) ->
+  [{Vsn, Desc, append_emqx_relup_instrs(CurrRelVsn, Vsn, Instrs)} || {Vsn, Desc, Instrs} <- RUs].
+
+%% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
+%% the instruction lists.
+append_emqx_relup_instrs(CurrRelVsn, Vsn, Instrs) ->
+  case lists:reverse(Instrs) of
+    [{apply, {emqx_relup, post_release_upgrade, _}} | _] ->
+      Instrs;
+    RInstrs ->
+      lists:reverse([instr_post_release_upgrade(CurrRelVsn, Vsn) | RInstrs])
+  end.
+
+instr_post_release_upgrade(CurrRelVsn, Vsn) ->
+  {apply, {emqx_relup, post_release_upgrade, [CurrRelVsn, Vsn]}}.
+
+term_to_text(Term) ->
+  io_lib:format("~p.", [Term]).
\ No newline at end of file

From 692d1e2a3371f633099d6bee2c06558e7f12ef22 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Sat, 26 Feb 2022 21:31:09 +0800
Subject: [PATCH 02/13] fix(relup): OTP_VSN: unbound variable

---
 scripts/relup-base-packages.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scripts/relup-base-packages.sh b/scripts/relup-base-packages.sh
index f86185e0a..2a47b5135 100755
--- a/scripts/relup-base-packages.sh
+++ b/scripts/relup-base-packages.sh
@@ -28,6 +28,7 @@ case $PROFILE in
 esac
 
 SYSTEM="${SYSTEM:-$(./scripts/get-distro.sh)}"
+OTP_VSN="${OTP_VSN:-$(./scripts/get-otp-vsn.sh)}"
 
 ARCH="${ARCH:-$(uname -m)}"
 case "$ARCH" in

From 2365d1e983d0d9c56c6de31bb94f04ef3ce31475 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Sun, 27 Feb 2022 09:28:35 +0800
Subject: [PATCH 03/13] fix(relup): inject relup only for the current rel vsn

---
 rebar.config.erl             | 17 +++++----
 scripts/inject-relup.escript | 68 ++++++++++++++++++++----------------
 2 files changed, 48 insertions(+), 37 deletions(-)

diff --git a/rebar.config.erl b/rebar.config.erl
index 11db1abb1..447e58f97 100644
--- a/rebar.config.erl
+++ b/rebar.config.erl
@@ -128,31 +128,34 @@ prod_compile_opts() ->
 prod_overrides() ->
     [{add, [ {erl_opts, [deterministic]}]}].
 
-relup_deps(Profile) ->
-    {post_hooks, [{"(linux|darwin|solaris|freebsd|netbsd|openbsd)", release,
-                        "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx"])}]}.
+relup_deps(Profile, Vsn) ->
+    InjectCmd = "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx", "releases", Vsn]),
+    {post_hooks,
+        [ {"(linux|darwin|solaris|freebsd|netbsd|openbsd)", relup, InjectCmd}
+        ]
+    }.
 
 profiles() ->
     Vsn = get_vsn(),
     [ {'emqx',          [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, cloud, bin)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx')
+                        , relup_deps('emqx', Vsn)
                         ]}
     , {'emqx-pkg',      [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, cloud, pkg)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx-pkg')
+                        , relup_deps('emqx-pkg', Vsn)
                         ]}
     , {'emqx-edge',     [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, edge, bin)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx-edge')
+                        , relup_deps('emqx-edge', Vsn)
                         ]}
     , {'emqx-edge-pkg', [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, edge, pkg)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx-edge-pkg')
+                        , relup_deps('emqx-edge-pkg', Vsn)
                         ]}
     , {check,           [ {erl_opts, common_compile_opts()}
                         ]}
diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index a7ba23689..86c541ada 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -8,51 +8,59 @@
 -define(INFO(FORMAT, ARGS), io:format(user, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
 
 usage() ->
-  "Usage: " ++ escript:script_name() ++ " <path-to-release-dir>".
+  "Usage: " ++ escript:script_name() ++ " <path-to-relup-file-or-dir>".
 
-main([Dir]) ->
-  case filelib:is_dir(Dir) of
-    true ->
-      ok = inject(Dir);
+main([DirOrFile]) ->
+  case filelib:is_dir(DirOrFile) of
+    true -> ok = inject_dir(DirOrFile);
     false ->
-      ?ERROR("not a valid dir: ~p", [Dir]),
-      erlang:halt(1)
+      case filelib:is_regular(DirOrFile) of
+        true -> inject_file(DirOrFile);
+        false ->
+          ?ERROR("not a valid file: ~p", [DirOrFile]),
+          erlang:halt(1)
+      end
   end;
 main(_Args) ->
   ?ERROR("~s", [usage()]),
   erlang:halt(1).
 
-inject(Dir) ->
-  RelupFiles = filelib:wildcard(filename:join([Dir, "releases", "*", "relup"])),
-  lists:foreach(fun(File) ->
-      case file:consult(File) of
-        {ok, [{CurrRelVsn, UpVsnRUs, DnVsnRUs}]} ->
-          ?INFO("injecting instructions to: ~p", [File]),
-          UpdatedContent = [{CurrRelVsn, inject_relup_instrs(CurrRelVsn, UpVsnRUs),
-                              inject_relup_instrs(CurrRelVsn, DnVsnRUs)}],
-          file:write_file("/tmp/" ++ filename:basename(File), term_to_text(UpdatedContent));
-        {ok, _BadFormat} ->
-          ?ERROR("bad formatted relup file: ~p", [File]);
-        {error, Reason} ->
-          ?ERROR("read relup file ~p failed: ~p", [File, Reason])
-      end
-    end, RelupFiles).
+inject_dir(Dir) ->
+  RelupFiles = filelib:wildcard(filename:join([Dir, "**", "relup"])),
+  lists:foreach(fun inject_file/1, RelupFiles).
 
-inject_relup_instrs(CurrRelVsn, RUs) ->
-  [{Vsn, Desc, append_emqx_relup_instrs(CurrRelVsn, Vsn, Instrs)} || {Vsn, Desc, Instrs} <- RUs].
+inject_file(File) ->
+  case file:script(File) of
+    {ok, {CurrRelVsn, UpVsnRUs, DnVsnRUs}} ->
+      ?INFO("injecting instructions to: ~p", [File]),
+      UpdatedContent = {CurrRelVsn, inject_relup_instrs(up, CurrRelVsn, UpVsnRUs),
+                          inject_relup_instrs(down, CurrRelVsn, DnVsnRUs)},
+      ok = file:write_file(File, term_to_text(UpdatedContent));
+    {ok, _BadFormat} ->
+      ?ERROR("bad formatted relup file: ~p", [File]);
+    {error, Reason} ->
+      ?ERROR("read relup file ~p failed: ~p", [File, Reason])
+  end.
+
+inject_relup_instrs(Type, CurrRelVsn, RUs) ->
+  [{Vsn, Desc, append_emqx_relup_instrs(Type, CurrRelVsn, Vsn, Instrs)} || {Vsn, Desc, Instrs} <- RUs].
 
 %% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
 %% the instruction lists.
-append_emqx_relup_instrs(CurrRelVsn, Vsn, Instrs) ->
+append_emqx_relup_instrs(Type, CurrRelVsn, Vsn, Instrs) ->
+  CallbackFun = relup_callback_func(Type),
   case lists:reverse(Instrs) of
-    [{apply, {emqx_relup, post_release_upgrade, _}} | _] ->
+    [{apply, {emqx_relup, CallbackFun, _}} | _] ->
       Instrs;
     RInstrs ->
-      lists:reverse([instr_post_release_upgrade(CurrRelVsn, Vsn) | RInstrs])
+      lists:reverse([ {load_object_code, {emqx, CurrRelVsn, [emqx_relup]}}
+                    , {load, {emqx_relup, brutal_purge, soft_purge}}
+                    , {apply, {emqx_relup, CallbackFun, [CurrRelVsn, Vsn]}}
+                    | RInstrs])
   end.
 
-instr_post_release_upgrade(CurrRelVsn, Vsn) ->
-  {apply, {emqx_relup, post_release_upgrade, [CurrRelVsn, Vsn]}}.
+relup_callback_func(up) -> post_release_upgrade;
+relup_callback_func(down) -> post_release_downgrade.
 
 term_to_text(Term) ->
-  io_lib:format("~p.", [Term]).
\ No newline at end of file
+  io_lib:format("~p.", [Term]).

From 17440b2b53da924343e8d58c64d29fa3ad70630d Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Sun, 27 Feb 2022 10:23:14 +0800
Subject: [PATCH 04/13] fix(relup): add module emqx_relup

---
 scripts/inject-relup.escript |  3 ++-
 src/emqx_relup.erl           | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 src/emqx_relup.erl

diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index 86c541ada..e414b9c31 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -49,13 +49,14 @@ inject_relup_instrs(Type, CurrRelVsn, RUs) ->
 %% the instruction lists.
 append_emqx_relup_instrs(Type, CurrRelVsn, Vsn, Instrs) ->
   CallbackFun = relup_callback_func(Type),
+  Extra = #{}, %% we may need some extended args
   case lists:reverse(Instrs) of
     [{apply, {emqx_relup, CallbackFun, _}} | _] ->
       Instrs;
     RInstrs ->
       lists:reverse([ {load_object_code, {emqx, CurrRelVsn, [emqx_relup]}}
                     , {load, {emqx_relup, brutal_purge, soft_purge}}
-                    , {apply, {emqx_relup, CallbackFun, [CurrRelVsn, Vsn]}}
+                    , {apply, {emqx_relup, CallbackFun, [CurrRelVsn, Vsn, Extra]}}
                     | RInstrs])
   end.
 
diff --git a/src/emqx_relup.erl b/src/emqx_relup.erl
new file mode 100644
index 000000000..e844ea0ba
--- /dev/null
+++ b/src/emqx_relup.erl
@@ -0,0 +1,17 @@
+-module(emqx_relup).
+
+-export([ post_release_upgrade/3
+        , post_release_downgrade/3
+        ]).
+
+post_release_upgrade(_CurrRelVsn, _FromVsn, _) ->
+    reload_components().
+
+post_release_downgrade(_CurrRelVsn, _ToVsn, _) ->
+    reload_components().
+
+reload_components() ->
+    io:format("reloading resource providers ..."),
+    emqx_rule_engine:load_providers(),
+    io:format("loading plugins ..."),
+    emqx_plugins:load().

From 28bd2fcfa463dc04a01bdb07d11521e51f0294d1 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Sun, 27 Feb 2022 20:04:21 +0800
Subject: [PATCH 05/13] fix(relup): release upgrade failed with
 {bad_lib_vsn,emqx,"4.4.2"}

---
 scripts/inject-relup.escript | 46 +++++++++++++++++++++++++++---------
 src/emqx_relup.erl           | 14 +++++++++--
 2 files changed, 47 insertions(+), 13 deletions(-)

diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index e414b9c31..1a2dae78a 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -30,38 +30,62 @@ inject_dir(Dir) ->
   lists:foreach(fun inject_file/1, RelupFiles).
 
 inject_file(File) ->
+  EmqxVsn = emqx_vsn_from_rel_file(File),
   case file:script(File) of
     {ok, {CurrRelVsn, UpVsnRUs, DnVsnRUs}} ->
       ?INFO("injecting instructions to: ~p", [File]),
-      UpdatedContent = {CurrRelVsn, inject_relup_instrs(up, CurrRelVsn, UpVsnRUs),
-                          inject_relup_instrs(down, CurrRelVsn, DnVsnRUs)},
+      UpdatedContent = {CurrRelVsn, inject_relup_instrs(up, EmqxVsn, CurrRelVsn, UpVsnRUs),
+                          inject_relup_instrs(down, EmqxVsn, CurrRelVsn, DnVsnRUs)},
       ok = file:write_file(File, term_to_text(UpdatedContent));
     {ok, _BadFormat} ->
-      ?ERROR("bad formatted relup file: ~p", [File]);
+      ?ERROR("bad formatted relup file: ~p", [File]),
+      error({bad_relup_format, File});
     {error, Reason} ->
-      ?ERROR("read relup file ~p failed: ~p", [File, Reason])
+      ?ERROR("read relup file ~p failed: ~p", [File, Reason]),
+      error({read_relup_error, Reason})
   end.
 
-inject_relup_instrs(Type, CurrRelVsn, RUs) ->
-  [{Vsn, Desc, append_emqx_relup_instrs(Type, CurrRelVsn, Vsn, Instrs)} || {Vsn, Desc, Instrs} <- RUs].
+inject_relup_instrs(Type, EmqxVsn, CurrRelVsn, RUs) ->
+  [{Vsn, Desc, append_emqx_relup_instrs(Type, EmqxVsn, CurrRelVsn, Vsn, Instrs)}
+   || {Vsn, Desc, Instrs} <- RUs].
 
 %% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
 %% the instruction lists.
-append_emqx_relup_instrs(Type, CurrRelVsn, Vsn, Instrs) ->
+append_emqx_relup_instrs(Type, EmqxVsn, CurrRelVsn, Vsn, Instrs) ->
   CallbackFun = relup_callback_func(Type),
   Extra = #{}, %% we may need some extended args
   case lists:reverse(Instrs) of
     [{apply, {emqx_relup, CallbackFun, _}} | _] ->
       Instrs;
     RInstrs ->
-      lists:reverse([ {load_object_code, {emqx, CurrRelVsn, [emqx_relup]}}
-                    , {load, {emqx_relup, brutal_purge, soft_purge}}
-                    , {apply, {emqx_relup, CallbackFun, [CurrRelVsn, Vsn, Extra]}}
-                    | RInstrs])
+      Instrs2 = lists:reverse(
+          [ {apply, {emqx_relup, CallbackFun, [CurrRelVsn, Vsn, Extra]}}
+          , {load, {emqx_relup, brutal_purge, soft_purge}}
+          | RInstrs]),
+      %% we have to put 'load_object_code' before 'point_of_no_return'
+      %% so here we simply put it to the beginning
+      [{load_object_code, {emqx, EmqxVsn, [emqx_relup]}} | Instrs2]
   end.
 
 relup_callback_func(up) -> post_release_upgrade;
 relup_callback_func(down) -> post_release_downgrade.
 
+emqx_vsn_from_rel_file(RelupFile) ->
+  RelDir = filename:dirname(RelupFile),
+  RelFile = filename:join([RelDir, "emqx.rel"]),
+  case file:script(RelFile) of
+    {ok, {release, {_RelName, _RelVsn}, _Erts, Apps}} ->
+      case lists:keysearch(emqx, 1, Apps) of
+        {value, {emqx, EmqxVsn}} ->
+          EmqxVsn;
+        false ->
+          error({emqx_vsn_cannot_found, RelFile})
+      end;
+    {ok, _BadFormat} ->
+      ?ERROR("bad formatted .rel file: ~p", [RelFile]);
+    {error, Reason} ->
+      ?ERROR("read .rel file ~p failed: ~p", [RelFile, Reason])
+  end.
+
 term_to_text(Term) ->
   io_lib:format("~p.", [Term]).
diff --git a/src/emqx_relup.erl b/src/emqx_relup.erl
index e844ea0ba..b435f8ae8 100644
--- a/src/emqx_relup.erl
+++ b/src/emqx_relup.erl
@@ -10,8 +10,18 @@ post_release_upgrade(_CurrRelVsn, _FromVsn, _) ->
 post_release_downgrade(_CurrRelVsn, _ToVsn, _) ->
     reload_components().
 
+-ifdef(EMQX_ENTERPRISE).
 reload_components() ->
-    io:format("reloading resource providers ..."),
+    io:format("reloading resource providers ...~n"),
     emqx_rule_engine:load_providers(),
-    io:format("loading plugins ..."),
+    io:format("reloading module providers ...~n"),
+    emqx_modules:load_providers(),
+    io:format("loading plugins ...~n"),
     emqx_plugins:load().
+-else.
+reload_components() ->
+    io:format("reloading resource providers ...~n"),
+    emqx_rule_engine:load_providers(),
+    io:format("loading plugins ...~n"),
+    emqx_plugins:load().
+-endif.

From b7d07d7a96f30b29e9611cf795b69b6e54456563 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Mon, 28 Feb 2022 10:05:41 +0800
Subject: [PATCH 06/13] fix(appup): remove the post relup scripts from
 emqx_dashboard.appup.src

The instructions have been move into module `emqx_relup`.
---
 lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src b/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src
index 902585ffb..270c65b5e 100644
--- a/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src
+++ b/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src
@@ -1,18 +1,11 @@
 %% -*- mode: erlang -*-
 {VSN,
  [ {<<".*">>,
-    %% load all plugins
-    %% NOTE: this depends on the fact that emqx_dashboard is always
-    %% the last application gets upgraded
-    [ {apply, {emqx_rule_engine, load_providers, []}}
-    , {restart_application, emqx_dashboard}
-    , {apply, {emqx_plugins, load, []}}
+    [ {restart_application, emqx_dashboard}
     ]}
  ],
  [ {<<".*">>,
-    [ {apply, {emqx_rule_engine, load_providers, []}}
-    , {restart_application, emqx_dashboard}
-    , {apply, {emqx_plugins, load, []}}
+    [ {restart_application, emqx_dashboard}
     ]}
  ]
-}.
+}.
\ No newline at end of file

From f25b8801b4a83e7a15e2a6a574f3d85460bc7336 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Mon, 28 Feb 2022 19:07:38 +0800
Subject: [PATCH 07/13] fix(build): also make SYSTEM configurable by env
 variable

---
 build                          | 2 +-
 scripts/pkg-full-vsn.sh        | 2 +-
 scripts/relup-base-packages.sh | 3 ++-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/build b/build
index a339f803b..b4c9d0548 100755
--- a/build
+++ b/build
@@ -18,7 +18,7 @@ cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")"
 PKG_VSN="${PKG_VSN:-$(./pkg-vsn.sh)}"
 export PKG_VSN
 
-SYSTEM="$(./scripts/get-distro.sh)"
+SYSTEM="${SYSTEM:-$(./scripts/get-distro.sh)}"
 
 ##
 ## Support RPM and Debian based linux systems
diff --git a/scripts/pkg-full-vsn.sh b/scripts/pkg-full-vsn.sh
index de32e11ef..e118643c9 100755
--- a/scripts/pkg-full-vsn.sh
+++ b/scripts/pkg-full-vsn.sh
@@ -27,7 +27,7 @@ esac
 cd -P -- "$(dirname -- "${BASH_SOURCE[0]}")/.."
 
 OTP_VSN="${OTP_VSN:-$(./scripts/get-otp-vsn.sh)}"
-SYSTEM="$(./scripts/get-distro.sh)"
+SYSTEM="${SYSTEM:-$(./scripts/get-distro.sh)}"
 
 UNAME="$(uname -m)"
 case "$UNAME" in
diff --git a/scripts/relup-base-packages.sh b/scripts/relup-base-packages.sh
index 2a47b5135..070f3926a 100755
--- a/scripts/relup-base-packages.sh
+++ b/scripts/relup-base-packages.sh
@@ -62,10 +62,11 @@ pushd _upgrade_base
 for tag in $(../scripts/relup-base-vsns.sh $EDITION | xargs echo -n); do
     filename="$PROFILE-${tag#[e|v]}-otp$OTP_VSN-$SYSTEM-$ARCH.zip"
     url="https://www.emqx.com/downloads/$DIR/${tag#[e|v]}/$filename"
-    echo "downloading base package from ${url} ..."
     if [ ! -f "$filename" ] && curl -I -m 10 -o /dev/null -s -w "%{http_code}" "${url}" | grep -q -oE "^[23]+" ; then
+        echo "downloading base package from ${url} ..."
         curl -L -o "${filename}" "${url}"
         if [ "$SYSTEM" != "centos6" ]; then
+            echo "downloading sha256 sum from ${url}.sha256 ..."
             curl -L -o "${filename}.sha256" "${url}.sha256"
             SUMSTR=$(cat "${filename}.sha256")
             echo "got sha265sum: ${SUMSTR}"

From a7791b6c586f238a5b2f172aff01ec480bccb477 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Tue, 1 Mar 2022 01:58:55 +0800
Subject: [PATCH 08/13] fix(relup): download to 4.4.0 failed with error
 bad_lib_vsn

---
 rebar.config.erl             |   2 +-
 scripts/inject-relup.escript | 175 +++++++++++++++++++++--------------
 src/emqx_relup.erl           |  10 +-
 3 files changed, 112 insertions(+), 75 deletions(-)

diff --git a/rebar.config.erl b/rebar.config.erl
index 447e58f97..32e3444d1 100644
--- a/rebar.config.erl
+++ b/rebar.config.erl
@@ -129,7 +129,7 @@ prod_overrides() ->
     [{add, [ {erl_opts, [deterministic]}]}].
 
 relup_deps(Profile, Vsn) ->
-    InjectCmd = "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx", "releases", Vsn]),
+    InjectCmd = "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx"]) ++ " " ++ Vsn,
     {post_hooks,
         [ {"(linux|darwin|solaris|freebsd|netbsd|openbsd)", relup, InjectCmd}
         ]
diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index 1a2dae78a..b860ab0d9 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -4,88 +4,123 @@
 
 -mode(compile).
 
--define(ERROR(FORMAT, ARGS), io:format(standard_error, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
--define(INFO(FORMAT, ARGS), io:format(user, "[inject-relup] " ++ FORMAT ++"~n", ARGS)).
+-define(ERROR(FORMAT, ARGS), io:format(standard_error, "[inject-relup] " ++ FORMAT ++ "~n", ARGS)).
+-define(INFO(FORMAT, ARGS), io:format(user, "[inject-relup] " ++ FORMAT ++ "~n", ARGS)).
 
 usage() ->
-  "Usage: " ++ escript:script_name() ++ " <path-to-relup-file-or-dir>".
+    "Usage: " ++ escript:script_name() ++ " <path-to-release-dir> <release-vsn>".
 
-main([DirOrFile]) ->
-  case filelib:is_dir(DirOrFile) of
-    true -> ok = inject_dir(DirOrFile);
-    false ->
-      case filelib:is_regular(DirOrFile) of
-        true -> inject_file(DirOrFile);
+main([RelRootDir, CurrRelVsn]) ->
+    case filelib:is_dir(filename:join([RelRootDir, "releases"])) andalso
+         filelib:is_dir(filename:join([RelRootDir, "lib"])) of
+        true ->
+            EmqxAppVsns = get_emqx_app_vsns(RelRootDir),
+            ok = inject_relup_file(RelRootDir, CurrRelVsn, EmqxAppVsns);
         false ->
-          ?ERROR("not a valid file: ~p", [DirOrFile]),
-          erlang:halt(1)
-      end
-  end;
+            ?ERROR("not a valid root dir of release: ~p, for example: _build/emqx/rel/emqx",
+                [RelRootDir]),
+            erlang:halt(1)
+    end;
 main(_Args) ->
-  ?ERROR("~s", [usage()]),
-  erlang:halt(1).
+    ?ERROR("~s", [usage()]),
+    erlang:halt(1).
 
-inject_dir(Dir) ->
-  RelupFiles = filelib:wildcard(filename:join([Dir, "**", "relup"])),
-  lists:foreach(fun inject_file/1, RelupFiles).
+inject_relup_file(RelRootDir, CurrRelVsn, EmqxAppVsns) ->
+    RelupFile = filename:join([RelRootDir, "releases", CurrRelVsn, "relup"]),
+    inject_file(RelupFile, EmqxAppVsns).
 
-inject_file(File) ->
-  EmqxVsn = emqx_vsn_from_rel_file(File),
-  case file:script(File) of
-    {ok, {CurrRelVsn, UpVsnRUs, DnVsnRUs}} ->
-      ?INFO("injecting instructions to: ~p", [File]),
-      UpdatedContent = {CurrRelVsn, inject_relup_instrs(up, EmqxVsn, CurrRelVsn, UpVsnRUs),
-                          inject_relup_instrs(down, EmqxVsn, CurrRelVsn, DnVsnRUs)},
-      ok = file:write_file(File, term_to_text(UpdatedContent));
-    {ok, _BadFormat} ->
-      ?ERROR("bad formatted relup file: ~p", [File]),
-      error({bad_relup_format, File});
-    {error, Reason} ->
-      ?ERROR("read relup file ~p failed: ~p", [File, Reason]),
-      error({read_relup_error, Reason})
-  end.
+inject_file(File, EmqxAppVsns) ->
+    case file:script(File) of
+        {ok, {CurrRelVsn, UpVsnRUs, DnVsnRUs}} ->
+            ?INFO("injecting instructions to: ~p", [File]),
+            UpdatedContent = {CurrRelVsn,
+                inject_relup_instrs(up, EmqxAppVsns, CurrRelVsn, UpVsnRUs),
+                inject_relup_instrs(down, EmqxAppVsns, CurrRelVsn, DnVsnRUs)},
+            file:write_file(File, term_to_text(UpdatedContent));
+        {ok, _BadFormat} ->
+            ?ERROR("bad formatted relup file: ~p", [File]),
+            error({bad_relup_format, File});
+        {error, enoent} ->
+            ?INFO("relup file not found: ~p", [File]),
+            ok;
+        {error, Reason} ->
+            ?ERROR("read relup file ~p failed: ~p", [File, Reason]),
+            error({read_relup_error, Reason})
+    end.
 
-inject_relup_instrs(Type, EmqxVsn, CurrRelVsn, RUs) ->
-  [{Vsn, Desc, append_emqx_relup_instrs(Type, EmqxVsn, CurrRelVsn, Vsn, Instrs)}
-   || {Vsn, Desc, Instrs} <- RUs].
+inject_relup_instrs(Type, EmqxAppVsns, CurrRelVsn, RUs) ->
+    lists:map(fun
+        ({Vsn, "(relup-injected) " ++ _ = Desc, Instrs}) -> %% already injected
+            {Vsn, Desc, Instrs};
+        ({Vsn, Desc, Instrs}) ->
+            {Vsn, "(relup-injected) " ++ Desc,
+                append_emqx_relup_instrs(Type, EmqxAppVsns, CurrRelVsn, Vsn, Instrs)}
+    end, RUs).
 
 %% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
 %% the instruction lists.
-append_emqx_relup_instrs(Type, EmqxVsn, CurrRelVsn, Vsn, Instrs) ->
-  CallbackFun = relup_callback_func(Type),
-  Extra = #{}, %% we may need some extended args
-  case lists:reverse(Instrs) of
-    [{apply, {emqx_relup, CallbackFun, _}} | _] ->
-      Instrs;
-    RInstrs ->
-      Instrs2 = lists:reverse(
-          [ {apply, {emqx_relup, CallbackFun, [CurrRelVsn, Vsn, Extra]}}
-          , {load, {emqx_relup, brutal_purge, soft_purge}}
-          | RInstrs]),
-      %% we have to put 'load_object_code' before 'point_of_no_return'
-      %% so here we simply put it to the beginning
-      [{load_object_code, {emqx, EmqxVsn, [emqx_relup]}} | Instrs2]
-  end.
+append_emqx_relup_instrs(up, EmqxAppVsns, CurrRelVsn, FromRelVsn, Instrs) ->
+    {EmqxVsn, true} = maps:get(CurrRelVsn, EmqxAppVsns),
+    Extra = #{}, %% we may need some extended args
+    %% we have to put 'load_object_code' before 'point_of_no_return'
+    %% so here we simply put it to the beginning
+    Instrs0 = [ {load_object_code, {emqx, EmqxVsn, [emqx_relup]}}
+              | Instrs],
+    Instrs0 ++
+        [ {load, {emqx_relup, brutal_purge, soft_purge}}
+        , {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, Extra]}}
+        ];
 
-relup_callback_func(up) -> post_release_upgrade;
-relup_callback_func(down) -> post_release_downgrade.
+append_emqx_relup_instrs(down, EmqxAppVsns, _CurrRelVsn, ToRelVsn, Instrs) ->
+    Extra = #{}, %% we may need some extended args
+    case maps:get(ToRelVsn, EmqxAppVsns) of
+        {EmqxVsn, true} ->
+            Instrs0 = [ {load_object_code, {emqx, EmqxVsn, [emqx_relup]}}
+                      | Instrs],
+            Instrs0 ++
+                [ {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}}
+                , {load, {emqx_relup, brutal_purge, soft_purge}}
+                ];
+        {_EmqxVsn, false} ->
+            Instrs ++
+                [ {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}}
+                , {remove, {emqx_relup, brutal_purge, soft_purge}}
+                ]
+    end.
 
-emqx_vsn_from_rel_file(RelupFile) ->
-  RelDir = filename:dirname(RelupFile),
-  RelFile = filename:join([RelDir, "emqx.rel"]),
-  case file:script(RelFile) of
-    {ok, {release, {_RelName, _RelVsn}, _Erts, Apps}} ->
-      case lists:keysearch(emqx, 1, Apps) of
-        {value, {emqx, EmqxVsn}} ->
-          EmqxVsn;
-        false ->
-          error({emqx_vsn_cannot_found, RelFile})
-      end;
-    {ok, _BadFormat} ->
-      ?ERROR("bad formatted .rel file: ~p", [RelFile]);
-    {error, Reason} ->
-      ?ERROR("read .rel file ~p failed: ~p", [RelFile, Reason])
-  end.
+get_emqx_app_vsns(RelRootDir) ->
+    RelFiles = filelib:wildcard(filename:join([RelRootDir, "releases", "*", "emqx.rel"])),
+    lists:foldl(fun(RelFile, AppVsns) ->
+        {ok, RelVsn, EmqxVsn} = read_emqx_vsn_from_rel_file(RelFile),
+        AppVsns#{RelVsn => {EmqxVsn, has_relup_module(RelRootDir, EmqxVsn)}}
+    end, #{}, RelFiles).
+
+read_emqx_vsn_from_rel_file(RelFile) ->
+    case file:script(RelFile) of
+        {ok, {release, {_RelName, RelVsn}, _Erts, Apps}} ->
+            case lists:keysearch(emqx, 1, Apps) of
+                {value, {emqx, EmqxVsn}} ->
+                    {ok, RelVsn, EmqxVsn};
+                false ->
+                    error({emqx_vsn_cannot_found, RelFile})
+            end;
+        {ok, _BadFormat} ->
+            ?ERROR("bad formatted .rel file: ~p", [RelFile]);
+        {error, Reason} ->
+            ?ERROR("read .rel file ~p failed: ~p", [RelFile, Reason])
+    end.
+
+has_relup_module(RelRootDir, EmqxVsn) ->
+    AppFile = filename:join([RelRootDir, "lib", "emqx-" ++ EmqxVsn, "ebin", "emqx.app"]),
+    case file:script(AppFile) of
+        {ok, {application, emqx, AppInfo}} ->
+            {value, {_, EmqxVsn}} = lists:keysearch(vsn, 1, AppInfo), %% assert
+            {value, {_, Modules}} = lists:keysearch(modules, 1, AppInfo),
+            lists:member(emqx_relup, Modules);
+        {error, Reason} ->
+            ?ERROR("read .app file ~p failed: ~p", [AppFile, Reason]),
+            error({read_app_file_error, AppFile, Reason})
+    end.
 
 term_to_text(Term) ->
-  io_lib:format("~p.", [Term]).
+    io_lib:format("~p.", [Term]).
diff --git a/src/emqx_relup.erl b/src/emqx_relup.erl
index b435f8ae8..66a5281da 100644
--- a/src/emqx_relup.erl
+++ b/src/emqx_relup.erl
@@ -1,13 +1,15 @@
 -module(emqx_relup).
 
--export([ post_release_upgrade/3
-        , post_release_downgrade/3
+-export([ post_release_upgrade/2
+        , post_release_downgrade/2
         ]).
 
-post_release_upgrade(_CurrRelVsn, _FromVsn, _) ->
+%% what to do after upgraded from a old release vsn.
+post_release_upgrade(_FromRelVsn, _) ->
     reload_components().
 
-post_release_downgrade(_CurrRelVsn, _ToVsn, _) ->
+%% what to do after downgraded to a old release vsn.
+post_release_downgrade(_ToRelVsn, _) ->
     reload_components().
 
 -ifdef(EMQX_ENTERPRISE).

From 769e79e2cd99f3e5a89f4a59574bfa6c49e6acd7 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Tue, 1 Mar 2022 15:09:04 +0800
Subject: [PATCH 09/13] chore(relup): also inject emqx_app automatically

---
 scripts/inject-relup.escript | 56 +++++++++++++++++++++++++-----------
 1 file changed, 39 insertions(+), 17 deletions(-)

diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index b860ab0d9..3a779d239 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -59,32 +59,54 @@ inject_relup_instrs(Type, EmqxAppVsns, CurrRelVsn, RUs) ->
 
 %% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
 %% the instruction lists.
-append_emqx_relup_instrs(up, EmqxAppVsns, CurrRelVsn, FromRelVsn, Instrs) ->
+append_emqx_relup_instrs(up, EmqxAppVsns, CurrRelVsn, FromRelVsn, Instrs0) ->
     {EmqxVsn, true} = maps:get(CurrRelVsn, EmqxAppVsns),
     Extra = #{}, %% we may need some extended args
+    LoadObjEmqxMods = {load_object_code, {emqx, EmqxVsn, [emqx_relup, emqx_app]}},
+    LoadCodeEmqxRelup = {load, {emqx_relup, brutal_purge, soft_purge}},
+    LoadCodeEmqxApp = {load, {emqx_app, brutal_purge, soft_purge}},
+    ApplyEmqxRelup = {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, Extra]}},
+    Instrs1 = Instrs0 -- [LoadCodeEmqxRelup, LoadCodeEmqxApp],
     %% we have to put 'load_object_code' before 'point_of_no_return'
-    %% so here we simply put it to the beginning
-    Instrs0 = [ {load_object_code, {emqx, EmqxVsn, [emqx_relup]}}
-              | Instrs],
-    Instrs0 ++
-        [ {load, {emqx_relup, brutal_purge, soft_purge}}
-        , {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, Extra]}}
+    %% so here we simply put them to the beginning of the instruction list
+    Instrs2 = [ LoadObjEmqxMods
+              | Instrs1],
+    %% the `load` must be put after the 'point_of_no_return'
+    Instrs2 ++
+        [ LoadCodeEmqxRelup
+        , LoadCodeEmqxApp
+        , ApplyEmqxRelup
         ];
 
-append_emqx_relup_instrs(down, EmqxAppVsns, _CurrRelVsn, ToRelVsn, Instrs) ->
+append_emqx_relup_instrs(down, EmqxAppVsns, _CurrRelVsn, ToRelVsn, Instrs0) ->
     Extra = #{}, %% we may need some extended args
+    ApplyEmqxRelup = {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}},
     case maps:get(ToRelVsn, EmqxAppVsns) of
         {EmqxVsn, true} ->
-            Instrs0 = [ {load_object_code, {emqx, EmqxVsn, [emqx_relup]}}
-                      | Instrs],
-            Instrs0 ++
-                [ {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}}
-                , {load, {emqx_relup, brutal_purge, soft_purge}}
+            LoadObjEmqxMods = {load_object_code, {emqx, EmqxVsn, [emqx_relup, emqx_app]}},
+            LoadCodeEmqxRelup = {load, {emqx_relup, brutal_purge, soft_purge}},
+            LoadCodeEmqxApp = {load, {emqx_app, brutal_purge, soft_purge}},
+            Instrs1 = Instrs0 -- [LoadCodeEmqxRelup, LoadCodeEmqxApp, ApplyEmqxRelup],
+            Instrs2 = [ LoadObjEmqxMods
+                      | Instrs1],
+            %% NOTE: We apply emqx_relup:post_release_downgrade/2 first, and then reload
+            %%  the old vsn code of emqx_relup.
+            Instrs2 ++
+                [ LoadCodeEmqxApp
+                , ApplyEmqxRelup
+                , LoadCodeEmqxRelup
                 ];
-        {_EmqxVsn, false} ->
-            Instrs ++
-                [ {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}}
-                , {remove, {emqx_relup, brutal_purge, soft_purge}}
+        {EmqxVsn, false} ->
+            LoadObjEmqxApp = {load_object_code, {emqx, EmqxVsn, [emqx_app]}},
+            LoadCodeEmqxApp = {load, {emqx_app, brutal_purge, soft_purge}},
+            RemoveCodeEmqxRelup = {remove, {emqx_relup, brutal_purge, soft_purge}},
+            Instrs1 = Instrs0 -- [LoadCodeEmqxApp, RemoveCodeEmqxRelup, ApplyEmqxRelup],
+            Instrs2 = [ LoadObjEmqxApp
+                      | Instrs1],
+            Instrs2 ++
+                [ LoadCodeEmqxApp
+                , ApplyEmqxRelup
+                , RemoveCodeEmqxRelup
                 ]
     end.
 

From 7698ad7c4b32701e8e3b3a25435d8d7d9bb135a1 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Tue, 1 Mar 2022 17:15:19 +0800
Subject: [PATCH 10/13] chore(relup): print more info after release upgrade
 complete

---
 src/emqx_relup.erl | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/emqx_relup.erl b/src/emqx_relup.erl
index 66a5281da..cb71c6305 100644
--- a/src/emqx_relup.erl
+++ b/src/emqx_relup.erl
@@ -4,26 +4,31 @@
         , post_release_downgrade/2
         ]).
 
+-define(INFO(FORMAT), io:format("[emqx_relup] " ++ FORMAT ++ "~n")).
+-define(INFO(FORMAT, ARGS), io:format("[emqx_relup] " ++ FORMAT ++ "~n", ARGS)).
+
 %% what to do after upgraded from a old release vsn.
 post_release_upgrade(_FromRelVsn, _) ->
+    ?INFO("emqx has been upgraded to ~s", [emqx_app:get_release()]),
     reload_components().
 
 %% what to do after downgraded to a old release vsn.
 post_release_downgrade(_ToRelVsn, _) ->
+    ?INFO("emqx has been downgrade to ~s", [emqx_app:get_release()]),
     reload_components().
 
 -ifdef(EMQX_ENTERPRISE).
 reload_components() ->
-    io:format("reloading resource providers ...~n"),
+    ?INFO("reloading resource providers ..."),
     emqx_rule_engine:load_providers(),
-    io:format("reloading module providers ...~n"),
+    ?INFO("reloading module providers ..."),
     emqx_modules:load_providers(),
-    io:format("loading plugins ...~n"),
+    ?INFO("loading plugins ..."),
     emqx_plugins:load().
 -else.
 reload_components() ->
-    io:format("reloading resource providers ...~n"),
+    ?INFO("reloading resource providers ..."),
     emqx_rule_engine:load_providers(),
-    io:format("loading plugins ...~n"),
+    ?INFO("loading plugins ..."),
     emqx_plugins:load().
 -endif.

From 41afbd2b13ddcbd77c911b9193c4cfa7a7e2f1d4 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Tue, 1 Mar 2022 22:01:00 +0800
Subject: [PATCH 11/13] refactor(relup): don't collect relvsn -> appvsn
 mappings

---
 build                                         |   3 +
 .../src/emqx_dashboard.appup.src              |   2 +-
 rebar.config.erl                              |  11 --
 scripts/inject-relup.escript                  | 165 +++++++-----------
 src/emqx.appup.src                            |  14 +-
 src/emqx_relup.erl                            |  30 +++-
 6 files changed, 107 insertions(+), 118 deletions(-)

diff --git a/build b/build
index b4c9d0548..8bf435357 100755
--- a/build
+++ b/build
@@ -136,6 +136,9 @@ make_zip() {
     local tarball="${relpath}/${tarname}"
     local target_zip="${pkgpath}/${pkgname}"
     tar zxf "${tarball}" -C "${tard}/emqx"
+    if ! [[ $SYSTEM == windows* ]]; then
+        ./scripts/inject-relup.escript "${tard}/emqx/releases/${PKG_VSN}/relup"
+    fi
     cp_dyn_libs "${tard}/emqx"
     pushd "${tard}" >/dev/null
     case "$SYSTEM" in
diff --git a/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src b/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src
index 270c65b5e..513757418 100644
--- a/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src
+++ b/lib-ce/emqx_dashboard/src/emqx_dashboard.appup.src
@@ -8,4 +8,4 @@
     [ {restart_application, emqx_dashboard}
     ]}
  ]
-}.
\ No newline at end of file
+}.
diff --git a/rebar.config.erl b/rebar.config.erl
index 32e3444d1..492707867 100644
--- a/rebar.config.erl
+++ b/rebar.config.erl
@@ -128,34 +128,23 @@ prod_compile_opts() ->
 prod_overrides() ->
     [{add, [ {erl_opts, [deterministic]}]}].
 
-relup_deps(Profile, Vsn) ->
-    InjectCmd = "scripts/inject-relup.escript " ++ filename:join(["_build", Profile, "rel", "emqx"]) ++ " " ++ Vsn,
-    {post_hooks,
-        [ {"(linux|darwin|solaris|freebsd|netbsd|openbsd)", relup, InjectCmd}
-        ]
-    }.
-
 profiles() ->
     Vsn = get_vsn(),
     [ {'emqx',          [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, cloud, bin)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx', Vsn)
                         ]}
     , {'emqx-pkg',      [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, cloud, pkg)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx-pkg', Vsn)
                         ]}
     , {'emqx-edge',     [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, edge, bin)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx-edge', Vsn)
                         ]}
     , {'emqx-edge-pkg', [ {erl_opts, prod_compile_opts()}
                         , {relx, relx(Vsn, edge, pkg)}
                         , {overrides, prod_overrides()}
-                        , relup_deps('emqx-edge-pkg', Vsn)
                         ]}
     , {check,           [ {erl_opts, common_compile_opts()}
                         ]}
diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index 3a779d239..93fe34a90 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -8,34 +8,27 @@
 -define(INFO(FORMAT, ARGS), io:format(user, "[inject-relup] " ++ FORMAT ++ "~n", ARGS)).
 
 usage() ->
-    "Usage: " ++ escript:script_name() ++ " <path-to-release-dir> <release-vsn>".
+    "Usage: " ++ escript:script_name() ++ " <path-to-relup-file>".
 
-main([RelRootDir, CurrRelVsn]) ->
-    case filelib:is_dir(filename:join([RelRootDir, "releases"])) andalso
-         filelib:is_dir(filename:join([RelRootDir, "lib"])) of
+main([RelupFile]) ->
+    case filelib:is_regular(RelupFile) of
         true ->
-            EmqxAppVsns = get_emqx_app_vsns(RelRootDir),
-            ok = inject_relup_file(RelRootDir, CurrRelVsn, EmqxAppVsns);
+            ok = inject_relup_file(RelupFile);
         false ->
-            ?ERROR("not a valid root dir of release: ~p, for example: _build/emqx/rel/emqx",
-                [RelRootDir]),
+            ?ERROR("not a valid file: ~p", [RelupFile]),
             erlang:halt(1)
     end;
 main(_Args) ->
     ?ERROR("~s", [usage()]),
     erlang:halt(1).
 
-inject_relup_file(RelRootDir, CurrRelVsn, EmqxAppVsns) ->
-    RelupFile = filename:join([RelRootDir, "releases", CurrRelVsn, "relup"]),
-    inject_file(RelupFile, EmqxAppVsns).
-
-inject_file(File, EmqxAppVsns) ->
+inject_relup_file(File) ->
     case file:script(File) of
         {ok, {CurrRelVsn, UpVsnRUs, DnVsnRUs}} ->
             ?INFO("injecting instructions to: ~p", [File]),
             UpdatedContent = {CurrRelVsn,
-                inject_relup_instrs(up, EmqxAppVsns, CurrRelVsn, UpVsnRUs),
-                inject_relup_instrs(down, EmqxAppVsns, CurrRelVsn, DnVsnRUs)},
+                inject_relup_instrs(up, UpVsnRUs),
+                inject_relup_instrs(down, DnVsnRUs)},
             file:write_file(File, term_to_text(UpdatedContent));
         {ok, _BadFormat} ->
             ?ERROR("bad formatted relup file: ~p", [File]),
@@ -48,101 +41,77 @@ inject_file(File, EmqxAppVsns) ->
             error({read_relup_error, Reason})
     end.
 
-inject_relup_instrs(Type, EmqxAppVsns, CurrRelVsn, RUs) ->
-    lists:map(fun
-        ({Vsn, "(relup-injected) " ++ _ = Desc, Instrs}) -> %% already injected
-            {Vsn, Desc, Instrs};
-        ({Vsn, Desc, Instrs}) ->
-            {Vsn, "(relup-injected) " ++ Desc,
-                append_emqx_relup_instrs(Type, EmqxAppVsns, CurrRelVsn, Vsn, Instrs)}
+inject_relup_instrs(Type, RUs) ->
+    lists:map(fun({Vsn, Desc, Instrs}) ->
+        {Vsn, Desc, append_emqx_relup_instrs(Type, Vsn, Instrs)}
     end, RUs).
 
 %% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
 %% the instruction lists.
-append_emqx_relup_instrs(up, EmqxAppVsns, CurrRelVsn, FromRelVsn, Instrs0) ->
-    {EmqxVsn, true} = maps:get(CurrRelVsn, EmqxAppVsns),
+append_emqx_relup_instrs(up, FromRelVsn, Instrs0) ->
     Extra = #{}, %% we may need some extended args
-    LoadObjEmqxMods = {load_object_code, {emqx, EmqxVsn, [emqx_relup, emqx_app]}},
-    LoadCodeEmqxRelup = {load, {emqx_relup, brutal_purge, soft_purge}},
-    LoadCodeEmqxApp = {load, {emqx_app, brutal_purge, soft_purge}},
-    ApplyEmqxRelup = {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, Extra]}},
-    Instrs1 = Instrs0 -- [LoadCodeEmqxRelup, LoadCodeEmqxApp],
-    %% we have to put 'load_object_code' before 'point_of_no_return'
-    %% so here we simply put them to the beginning of the instruction list
-    Instrs2 = [ LoadObjEmqxMods
-              | Instrs1],
-    %% the `load` must be put after the 'point_of_no_return'
-    Instrs2 ++
-        [ LoadCodeEmqxRelup
-        , LoadCodeEmqxApp
-        , ApplyEmqxRelup
+    filter_and_check_instrs(up, Instrs0) ++
+        [ {load, {emqx_app, brutal_purge, soft_purge}}
+        , {load, {emqx_relup, brutal_purge, soft_purge}}
+        , {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, Extra]}}
         ];
 
-append_emqx_relup_instrs(down, EmqxAppVsns, _CurrRelVsn, ToRelVsn, Instrs0) ->
+append_emqx_relup_instrs(down, ToRelVsn, Instrs0) ->
     Extra = #{}, %% we may need some extended args
-    ApplyEmqxRelup = {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}},
-    case maps:get(ToRelVsn, EmqxAppVsns) of
-        {EmqxVsn, true} ->
-            LoadObjEmqxMods = {load_object_code, {emqx, EmqxVsn, [emqx_relup, emqx_app]}},
-            LoadCodeEmqxRelup = {load, {emqx_relup, brutal_purge, soft_purge}},
-            LoadCodeEmqxApp = {load, {emqx_app, brutal_purge, soft_purge}},
-            Instrs1 = Instrs0 -- [LoadCodeEmqxRelup, LoadCodeEmqxApp, ApplyEmqxRelup],
-            Instrs2 = [ LoadObjEmqxMods
-                      | Instrs1],
-            %% NOTE: We apply emqx_relup:post_release_downgrade/2 first, and then reload
-            %%  the old vsn code of emqx_relup.
-            Instrs2 ++
-                [ LoadCodeEmqxApp
-                , ApplyEmqxRelup
-                , LoadCodeEmqxRelup
-                ];
-        {EmqxVsn, false} ->
-            LoadObjEmqxApp = {load_object_code, {emqx, EmqxVsn, [emqx_app]}},
-            LoadCodeEmqxApp = {load, {emqx_app, brutal_purge, soft_purge}},
-            RemoveCodeEmqxRelup = {remove, {emqx_relup, brutal_purge, soft_purge}},
-            Instrs1 = Instrs0 -- [LoadCodeEmqxApp, RemoveCodeEmqxRelup, ApplyEmqxRelup],
-            Instrs2 = [ LoadObjEmqxApp
-                      | Instrs1],
-            Instrs2 ++
-                [ LoadCodeEmqxApp
-                , ApplyEmqxRelup
-                , RemoveCodeEmqxRelup
-                ]
+    %% NOTE: When downgrading, we apply emqx_relup:post_release_downgrade/2 before reloading
+    %%  or removing the emqx_relup module.
+    Instrs1 = filter_and_check_instrs(down, Instrs0) ++
+        [ {load, {emqx_app, brutal_purge, soft_purge}}
+        , {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}}
+        ],
+    %% emqx_relup does not exist before release "4.4.2"
+    LoadInsts =
+        case ToRelVsn of
+            ToRelVsn when ToRelVsn =:= "4.4.1"; ToRelVsn =:= "4.4.0" ->
+                [{remove, {emqx_relup, brutal_purge, brutal_purge}}];
+            _ ->
+                [{load, {emqx_relup, brutal_purge, soft_purge}}]
+        end,
+    Instrs1 ++ LoadInsts.
+
+filter_and_check_instrs(Type, Instrs) ->
+    case take_emqx_vsn_and_modules(Instrs) of
+        {EmqxAppVsn, EmqxMods, RemainInstrs} when EmqxAppVsn =/= not_found, EmqxMods =/= [] ->
+            assert_mandatory_modules(Type, EmqxMods),
+            [{load_object_code, {emqx, EmqxAppVsn, EmqxMods}} | RemainInstrs];
+        {_, _, _} ->
+            ?ERROR("cannot found 'load_module' instructions for app emqx", []),
+            error({instruction_not_found, load_object_code})
     end.
 
-get_emqx_app_vsns(RelRootDir) ->
-    RelFiles = filelib:wildcard(filename:join([RelRootDir, "releases", "*", "emqx.rel"])),
-    lists:foldl(fun(RelFile, AppVsns) ->
-        {ok, RelVsn, EmqxVsn} = read_emqx_vsn_from_rel_file(RelFile),
-        AppVsns#{RelVsn => {EmqxVsn, has_relup_module(RelRootDir, EmqxVsn)}}
-    end, #{}, RelFiles).
+take_emqx_vsn_and_modules(Instrs) ->
+    lists:foldl(fun
+        ({load_object_code, {emqx, AppVsn, Mods}}, {_EmqxAppVsn, EmqxMods, RemainInstrs}) ->
+            {AppVsn, EmqxMods ++ Mods, RemainInstrs};
+        ({load, {Mod, _, _}}, {EmqxAppVsn, EmqxMods, RemainInstrs})
+                when Mod =:= emqx_relup; Mod =:= emqx_app ->
+            {EmqxAppVsn, EmqxMods, RemainInstrs};
+        ({remove, {emqx_relup, _, _}}, {EmqxAppVsn, EmqxMods, RemainInstrs}) ->
+            {EmqxAppVsn, EmqxMods, RemainInstrs};
+        ({apply, {emqx_relup, _, _}}, {EmqxAppVsn, EmqxMods, RemainInstrs}) ->
+            {EmqxAppVsn, EmqxMods, RemainInstrs};
+        (Instr, {EmqxAppVsn, EmqxMods, RemainInstrs}) ->
+            {EmqxAppVsn, EmqxMods, RemainInstrs ++ [Instr]}
+    end, {not_found, [], []}, Instrs).
 
-read_emqx_vsn_from_rel_file(RelFile) ->
-    case file:script(RelFile) of
-        {ok, {release, {_RelName, RelVsn}, _Erts, Apps}} ->
-            case lists:keysearch(emqx, 1, Apps) of
-                {value, {emqx, EmqxVsn}} ->
-                    {ok, RelVsn, EmqxVsn};
-                false ->
-                    error({emqx_vsn_cannot_found, RelFile})
-            end;
-        {ok, _BadFormat} ->
-            ?ERROR("bad formatted .rel file: ~p", [RelFile]);
-        {error, Reason} ->
-            ?ERROR("read .rel file ~p failed: ~p", [RelFile, Reason])
-    end.
+assert_mandatory_modules(up, Mods) ->
+    assert(lists:member(emqx_relup, Mods) andalso lists:member(emqx_app, Mods),
+        "cannot found 'load_module' instructions for emqx_app and emqx_rel: ~p", [Mods]);
 
-has_relup_module(RelRootDir, EmqxVsn) ->
-    AppFile = filename:join([RelRootDir, "lib", "emqx-" ++ EmqxVsn, "ebin", "emqx.app"]),
-    case file:script(AppFile) of
-        {ok, {application, emqx, AppInfo}} ->
-            {value, {_, EmqxVsn}} = lists:keysearch(vsn, 1, AppInfo), %% assert
-            {value, {_, Modules}} = lists:keysearch(modules, 1, AppInfo),
-            lists:member(emqx_relup, Modules);
-        {error, Reason} ->
-            ?ERROR("read .app file ~p failed: ~p", [AppFile, Reason]),
-            error({read_app_file_error, AppFile, Reason})
-    end.
+assert_mandatory_modules(down, Mods) ->
+    assert(lists:member(emqx_app, Mods),
+        "cannot found 'load_module' instructions for emqx_app", []).
+
+assert(true, _, _) ->
+    ok;
+assert(false, Msg, Args) ->
+    ?ERROR(Msg, Args),
+    error(assert_failed).
 
 term_to_text(Term) ->
     io_lib:format("~p.", [Term]).
diff --git a/src/emqx.appup.src b/src/emqx.appup.src
index b9d4f5a16..53b4a9ff7 100644
--- a/src/emqx.appup.src
+++ b/src/emqx.appup.src
@@ -1,7 +1,9 @@
 %% -*- mode: erlang -*-
 {VSN,
   [{"4.4.1",
-    [{load_module,emqx_os_mon,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_app,brutal_purge,soft_purge,[]},
+     {add_module,emqx_relup},
+     {load_module,emqx_os_mon,brutal_purge,soft_purge,[]},
      {load_module,emqx_pmon,brutal_purge,soft_purge,[]},
      {load_module,emqx_cm,brutal_purge,soft_purge,[]},
      {load_module,emqx_sys_mon,brutal_purge,soft_purge,[]},
@@ -10,7 +12,8 @@
      {load_module,emqx_ctl,brutal_purge,soft_purge,[]},
      {load_module,emqx_channel,brutal_purge,soft_purge,[]}]},
    {"4.4.0",
-    [{load_module,emqx_pmon,brutal_purge,soft_purge,[]},
+    [{add_module,emqx_relup},
+     {load_module,emqx_pmon,brutal_purge,soft_purge,[]},
      {load_module,emqx_cm,brutal_purge,soft_purge,[]},
      {load_module,emqx_sys_mon,brutal_purge,soft_purge,[]},
      {load_module,emqx_vm_mon,brutal_purge,soft_purge,[]},
@@ -31,7 +34,9 @@
      {load_module,emqx_limiter,brutal_purge,soft_purge,[]}]},
    {<<".*">>,[]}],
   [{"4.4.1",
-    [{load_module,emqx_os_mon,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_app,brutal_purge,soft_purge,[]},
+     {delete_module,emqx_relup},
+     {load_module,emqx_os_mon,brutal_purge,soft_purge,[]},
      {load_module,emqx_pmon,brutal_purge,soft_purge,[]},
      {load_module,emqx_cm,brutal_purge,soft_purge,[]},
      {load_module,emqx_sys_mon,brutal_purge,soft_purge,[]},
@@ -40,7 +45,8 @@
      {load_module,emqx_ctl,brutal_purge,soft_purge,[]},
      {load_module,emqx_channel,brutal_purge,soft_purge,[]}]},
    {"4.4.0",
-    [{load_module,emqx_pmon,brutal_purge,soft_purge,[]},
+    [{delete_module,emqx_relup},
+     {load_module,emqx_pmon,brutal_purge,soft_purge,[]},
      {load_module,emqx_cm,brutal_purge,soft_purge,[]},
      {load_module,emqx_sys_mon,brutal_purge,soft_purge,[]},
      {load_module,emqx_vm_mon,brutal_purge,soft_purge,[]},
diff --git a/src/emqx_relup.erl b/src/emqx_relup.erl
index cb71c6305..dc443947a 100644
--- a/src/emqx_relup.erl
+++ b/src/emqx_relup.erl
@@ -1,5 +1,25 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2017-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
 -module(emqx_relup).
 
+%% NOTE: DO NOT remove this `-include`.
+%% We use this to forece this module to upgraded every release.
+-include("emqx_release.hrl").
+
 -export([ post_release_upgrade/2
         , post_release_downgrade/2
         ]).
@@ -8,13 +28,15 @@
 -define(INFO(FORMAT, ARGS), io:format("[emqx_relup] " ++ FORMAT ++ "~n", ARGS)).
 
 %% what to do after upgraded from a old release vsn.
-post_release_upgrade(_FromRelVsn, _) ->
-    ?INFO("emqx has been upgraded to ~s", [emqx_app:get_release()]),
+post_release_upgrade(FromRelVsn, _) ->
+    {_, CurrRelVsn} = ?EMQX_RELEASE,
+    ?INFO("emqx has been upgraded to from ~s to ~s!", [FromRelVsn, CurrRelVsn]),
     reload_components().
 
 %% what to do after downgraded to a old release vsn.
-post_release_downgrade(_ToRelVsn, _) ->
-    ?INFO("emqx has been downgrade to ~s", [emqx_app:get_release()]),
+post_release_downgrade(ToRelVsn, _) ->
+    {_, CurrRelVsn} = ?EMQX_RELEASE,
+    ?INFO("emqx has been downgraded to from ~s to ~s!", [CurrRelVsn, ToRelVsn]),
     reload_components().
 
 -ifdef(EMQX_ENTERPRISE).

From 77e3c1d3ac35888097b958201f1e8a2bee066b55 Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Wed, 2 Mar 2022 10:48:10 +0800
Subject: [PATCH 12/13] feat(relup): support providing 'Extra' parameter from
 appup.src

---
 scripts/inject-relup.escript | 68 +++++++++++++++++++++---------------
 src/emqx_relup.erl           |  6 ++--
 2 files changed, 43 insertions(+), 31 deletions(-)

diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index 93fe34a90..32c944246 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -49,20 +49,20 @@ inject_relup_instrs(Type, RUs) ->
 %% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
 %% the instruction lists.
 append_emqx_relup_instrs(up, FromRelVsn, Instrs0) ->
-    Extra = #{}, %% we may need some extended args
-    filter_and_check_instrs(up, Instrs0) ++
+     {{UpExtra, _}, Instrs1} = filter_and_check_instrs(up, Instrs0),
+     Instrs1 ++
         [ {load, {emqx_app, brutal_purge, soft_purge}}
         , {load, {emqx_relup, brutal_purge, soft_purge}}
-        , {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, Extra]}}
+        , {apply, {emqx_relup, post_release_upgrade, [FromRelVsn, UpExtra]}}
         ];
 
 append_emqx_relup_instrs(down, ToRelVsn, Instrs0) ->
-    Extra = #{}, %% we may need some extended args
+    {{_, DnExtra}, Instrs1} = filter_and_check_instrs(down, Instrs0)
     %% NOTE: When downgrading, we apply emqx_relup:post_release_downgrade/2 before reloading
     %%  or removing the emqx_relup module.
-    Instrs1 = filter_and_check_instrs(down, Instrs0) ++
+    Instrs1 ++
         [ {load, {emqx_app, brutal_purge, soft_purge}}
-        , {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, Extra]}}
+        , {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, DnExtra]}}
         ],
     %% emqx_relup does not exist before release "4.4.2"
     LoadInsts =
@@ -75,37 +75,49 @@ append_emqx_relup_instrs(down, ToRelVsn, Instrs0) ->
     Instrs1 ++ LoadInsts.
 
 filter_and_check_instrs(Type, Instrs) ->
-    case take_emqx_vsn_and_modules(Instrs) of
-        {EmqxAppVsn, EmqxMods, RemainInstrs} when EmqxAppVsn =/= not_found, EmqxMods =/= [] ->
+    case filter_fetch_emqx_mods_and_extra(Instrs) of
+        {_, _, [], _} ->
+            ?ERROR("cannot find any 'load_object_code' instructions for app emqx", []),
+            error({instruction_not_found, load_object_code});
+        {UpExtra, DnExtra, EmqxMods, RemainInstrs} ->
             assert_mandatory_modules(Type, EmqxMods),
-            [{load_object_code, {emqx, EmqxAppVsn, EmqxMods}} | RemainInstrs];
-        {_, _, _} ->
-            ?ERROR("cannot found 'load_module' instructions for app emqx", []),
-            error({instruction_not_found, load_object_code})
+            {{UpExtra, DnExtra}, RemainInstrs}
     end.
 
-take_emqx_vsn_and_modules(Instrs) ->
-    lists:foldl(fun
-        ({load_object_code, {emqx, AppVsn, Mods}}, {_EmqxAppVsn, EmqxMods, RemainInstrs}) ->
-            {AppVsn, EmqxMods ++ Mods, RemainInstrs};
-        ({load, {Mod, _, _}}, {EmqxAppVsn, EmqxMods, RemainInstrs})
-                when Mod =:= emqx_relup; Mod =:= emqx_app ->
-            {EmqxAppVsn, EmqxMods, RemainInstrs};
-        ({remove, {emqx_relup, _, _}}, {EmqxAppVsn, EmqxMods, RemainInstrs}) ->
-            {EmqxAppVsn, EmqxMods, RemainInstrs};
-        ({apply, {emqx_relup, _, _}}, {EmqxAppVsn, EmqxMods, RemainInstrs}) ->
-            {EmqxAppVsn, EmqxMods, RemainInstrs};
-        (Instr, {EmqxAppVsn, EmqxMods, RemainInstrs}) ->
-            {EmqxAppVsn, EmqxMods, RemainInstrs ++ [Instr]}
-    end, {not_found, [], []}, Instrs).
+filter_fetch_emqx_mods_and_extra(Instrs) ->
+    lists:foldl(fun do_filter_and_get/2, {UpExtra, DnExtra, [], []}, Instrs).
+
+%% collect modules for emqx app
+do_filter_and_get({load_object_code, {emqx, _AppVsn, Mods}} = Instr,
+        {UpExtra, DnExtra, EmqxMods, RemainInstrs}) ->
+    {UpExtra, DnExtra, EmqxMods ++ Mods, RemainInstrs ++ [Instr]};
+%% remove 'load' instrs
+do_filter_and_get({load, {Mod, _, _}}, {UpExtra, DnExtra, EmqxMods, RemainInstrs})
+        when Mod =:= emqx_relup; Mod =:= emqx_app ->
+    {UpExtra, DnExtra, EmqxMods, RemainInstrs};
+%% remove 'remove' instrs
+do_filter_and_get({remove, {emqx_relup, _, _}}, {UpExtra, DnExtra, EmqxMods, RemainInstrs}) ->
+    {UpExtra, DnExtra, EmqxMods, RemainInstrs};
+%% remove 'apply' instrs for upgrade, and collect the 'Extra' parameter
+do_filter_and_get({apply, {emqx_relup, post_release_upgrade, [_, UpExtra0]}},
+        {_, DnExtra, EmqxMods, RemainInstrs}) ->
+    {UpExtra0, DnExtra, EmqxMods, RemainInstrs};
+%% remove 'apply' instrs for downgrade, and collect the 'Extra' parameter
+do_filter_and_get({apply, {emqx_relup, post_release_downgrade, [_, DnExtra0]}},
+        {UpExtra, _, EmqxMods, RemainInstrs}) ->
+    {UpExtra, DnExtra0, EmqxMods, RemainInstrs};
+%% keep all other instrs unchanged
+do_filter_and_get(Instr, {UpExtra, DnExtra, EmqxMods, RemainInstrs}) ->
+    {UpExtra, DnExtra, EmqxMods, RemainInstrs ++ [Instr]}.
+
 
 assert_mandatory_modules(up, Mods) ->
     assert(lists:member(emqx_relup, Mods) andalso lists:member(emqx_app, Mods),
-        "cannot found 'load_module' instructions for emqx_app and emqx_rel: ~p", [Mods]);
+        "cannot find any 'load_object_code' instructions for emqx_app and emqx_rel: ~p", [Mods]);
 
 assert_mandatory_modules(down, Mods) ->
     assert(lists:member(emqx_app, Mods),
-        "cannot found 'load_module' instructions for emqx_app", []).
+        "cannot find any 'load_object_code' instructions for emqx_app", []).
 
 assert(true, _, _) ->
     ok;
diff --git a/src/emqx_relup.erl b/src/emqx_relup.erl
index dc443947a..fcc90d088 100644
--- a/src/emqx_relup.erl
+++ b/src/emqx_relup.erl
@@ -17,7 +17,7 @@
 -module(emqx_relup).
 
 %% NOTE: DO NOT remove this `-include`.
-%% We use this to forece this module to upgraded every release.
+%% We use this to force this module to be upgraded every release.
 -include("emqx_release.hrl").
 
 -export([ post_release_upgrade/2
@@ -27,13 +27,13 @@
 -define(INFO(FORMAT), io:format("[emqx_relup] " ++ FORMAT ++ "~n")).
 -define(INFO(FORMAT, ARGS), io:format("[emqx_relup] " ++ FORMAT ++ "~n", ARGS)).
 
-%% what to do after upgraded from a old release vsn.
+%% What to do after upgraded from an old release vsn.
 post_release_upgrade(FromRelVsn, _) ->
     {_, CurrRelVsn} = ?EMQX_RELEASE,
     ?INFO("emqx has been upgraded to from ~s to ~s!", [FromRelVsn, CurrRelVsn]),
     reload_components().
 
-%% what to do after downgraded to a old release vsn.
+%% What to do after downgraded to an old release vsn.
 post_release_downgrade(ToRelVsn, _) ->
     {_, CurrRelVsn} = ?EMQX_RELEASE,
     ?INFO("emqx has been downgraded to from ~s to ~s!", [CurrRelVsn, ToRelVsn]),

From 8be8f538a101ab138d1e0a21822b52f0e653ab7b Mon Sep 17 00:00:00 2001
From: Shawn <506895667@qq.com>
Date: Wed, 2 Mar 2022 11:36:42 +0800
Subject: [PATCH 13/13] fix(relup): verify emqx_relup call in upgrade and
 downgrade clauses

---
 scripts/inject-relup.escript | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/scripts/inject-relup.escript b/scripts/inject-relup.escript
index 32c944246..e2d3de795 100755
--- a/scripts/inject-relup.escript
+++ b/scripts/inject-relup.escript
@@ -46,8 +46,6 @@ inject_relup_instrs(Type, RUs) ->
         {Vsn, Desc, append_emqx_relup_instrs(Type, Vsn, Instrs)}
     end, RUs).
 
-%% The `{apply, emqx_relup, post_release_upgrade, []}` will be appended to the end of
-%% the instruction lists.
 append_emqx_relup_instrs(up, FromRelVsn, Instrs0) ->
      {{UpExtra, _}, Instrs1} = filter_and_check_instrs(up, Instrs0),
      Instrs1 ++
@@ -57,10 +55,10 @@ append_emqx_relup_instrs(up, FromRelVsn, Instrs0) ->
         ];
 
 append_emqx_relup_instrs(down, ToRelVsn, Instrs0) ->
-    {{_, DnExtra}, Instrs1} = filter_and_check_instrs(down, Instrs0)
+    {{_, DnExtra}, Instrs1} = filter_and_check_instrs(down, Instrs0),
     %% NOTE: When downgrading, we apply emqx_relup:post_release_downgrade/2 before reloading
     %%  or removing the emqx_relup module.
-    Instrs1 ++
+    Instrs2 = Instrs1 ++
         [ {load, {emqx_app, brutal_purge, soft_purge}}
         , {apply, {emqx_relup, post_release_downgrade, [ToRelVsn, DnExtra]}}
         ],
@@ -68,14 +66,24 @@ append_emqx_relup_instrs(down, ToRelVsn, Instrs0) ->
     LoadInsts =
         case ToRelVsn of
             ToRelVsn when ToRelVsn =:= "4.4.1"; ToRelVsn =:= "4.4.0" ->
-                [{remove, {emqx_relup, brutal_purge, brutal_purge}}];
+                [ {remove, {emqx_relup, brutal_purge, brutal_purge}}
+                , {purge, [emqx_relup]}
+                ];
             _ ->
                 [{load, {emqx_relup, brutal_purge, soft_purge}}]
         end,
-    Instrs1 ++ LoadInsts.
+    Instrs2 ++ LoadInsts.
 
 filter_and_check_instrs(Type, Instrs) ->
     case filter_fetch_emqx_mods_and_extra(Instrs) of
+        {_, DnExtra, _, _} when Type =:= up, DnExtra =/= undefined ->
+            ?ERROR("got '{apply,{emqx_relup,post_release_downgrade,[_,Extra]}}'"
+                   " from the upgrade instruction list, should be 'post_release_upgrade'", []),
+            error({instruction_not_found, load_object_code});
+        {UpExtra, _, _, _} when Type =:= down, UpExtra =/= undefined ->
+            ?ERROR("got '{apply,{emqx_relup,post_release_upgrade,[_,Extra]}}'"
+                   " from the downgrade instruction list, should be 'post_release_downgrade'", []),
+            error({instruction_not_found, load_object_code});
         {_, _, [], _} ->
             ?ERROR("cannot find any 'load_object_code' instructions for app emqx", []),
             error({instruction_not_found, load_object_code});
@@ -85,19 +93,21 @@ filter_and_check_instrs(Type, Instrs) ->
     end.
 
 filter_fetch_emqx_mods_and_extra(Instrs) ->
-    lists:foldl(fun do_filter_and_get/2, {UpExtra, DnExtra, [], []}, Instrs).
+    lists:foldl(fun do_filter_and_get/2, {undefined, undefined, [], []}, Instrs).
 
 %% collect modules for emqx app
 do_filter_and_get({load_object_code, {emqx, _AppVsn, Mods}} = Instr,
         {UpExtra, DnExtra, EmqxMods, RemainInstrs}) ->
     {UpExtra, DnExtra, EmqxMods ++ Mods, RemainInstrs ++ [Instr]};
-%% remove 'load' instrs
+%% remove 'load' instrs for emqx_relup and emqx_app
 do_filter_and_get({load, {Mod, _, _}}, {UpExtra, DnExtra, EmqxMods, RemainInstrs})
         when Mod =:= emqx_relup; Mod =:= emqx_app ->
     {UpExtra, DnExtra, EmqxMods, RemainInstrs};
-%% remove 'remove' instrs
+%% remove 'remove' and 'purge' instrs for emqx_relup
 do_filter_and_get({remove, {emqx_relup, _, _}}, {UpExtra, DnExtra, EmqxMods, RemainInstrs}) ->
     {UpExtra, DnExtra, EmqxMods, RemainInstrs};
+do_filter_and_get({purge, [emqx_relup]}, {UpExtra, DnExtra, EmqxMods, RemainInstrs}) ->
+    {UpExtra, DnExtra, EmqxMods, RemainInstrs};
 %% remove 'apply' instrs for upgrade, and collect the 'Extra' parameter
 do_filter_and_get({apply, {emqx_relup, post_release_upgrade, [_, UpExtra0]}},
         {_, DnExtra, EmqxMods, RemainInstrs}) ->